package overview;

import oop4.Circle;
import oop4.Tiger;

/**
 * @author oldliu
 * @since 1.0
 */
public class NullTest {
    public static void main(String[] args) {
        Circle c=null;
//        Object o=c;
//        Tiger t=(Tiger)o;
//        System.out.println(t);
//        System.out.println("面积是"+c.getArea());
        System.out.println(c.PI);
        c.printPI();

    }
}
